Electronic counter



June 30, J; 'R DESCH ELECTRONIC COUNTER 2 Sheets-Sheet 1 Filed Dec. 4,1951 INVENTOR JOSEPH R. DESGH n/wb Hls ATTORNEYS June 30, 1953 J. R.DEscH ELECTRONIC COUNTER 2 Sheets-Sheet 2 Filed Dec. 4, 1951 INVENTORJOSEPH R. DESCH HIS ATTORNEYS Patented June 30, 1953 ELECTRONIC COUNTERJoseph R. Desch, Dayton, Ohio, assignor to The National Cash RegisterCompany, Dayton, Ohio, a corporation of Maryland Application December 4,1951, serial No. 259,857

21 claims. (c1. 3154201) This invention relates to a novel electron tubecounting circuit and in particular to a circuit employing cold-cathodegas tubes connected in a ring or chain for sequential operation oneafter another in response to inputirnpulses.

The principal advantage of the novel count-, ing circuit lies in itssimplicity, the input impulses being applied to an entry device which inturn controls the stepping of the ring. In the novel circuit, the ringor chain is of extremely simple construction, since it requires only tworesistors apart from the tubes, and this is true whether there be fourtubes or more than -four tubes in the ring or chain. v

Briefly, the novel ring or chain circuit utilizes cold-cathode tubes ofthe type having at least an anode, a cathode, an igniter electrode, anda probe electrode, In these tubes, the igniter and the cathode form astarter gap by which ionization can be induced in a tube, and the vanode and the cathode form the main gap, to which ionization spreads'when the tube is operating. The tubes of the ring or chain are dividedintov two operational groups, with the cathodes of the tubes of eachgroup being connected together and to ground over a resistor which iscommon to the group, and with the anodes of each group connectedtogether to a separate source of anode potential for each group.

The tubes, which arel positive-grid tubes, are connected into anoperative chain by floating connections between the tubes, whichconnections extend from the probe of a tube 'of one group to the igniterof a tube of the 'other group. In case of a ring, the probe of the lasttube, which is in one group, is connected to the igniter of the firsttube, which is in the other group, and, if the ring is to control someother device to produce an output signal for each cycle of operation ofthe ring, this connection can include a rectifier to insure that theproper control will be obtained. These oating connections are simpledirect connections, which contain no impedance elements and have noadditional connections to potential sources. They cause the sequentialoperation of the tubes to take place in the desired order by enablingthe probe electrode in a conducting tube to so inuence the igniter inthe starting gap of the next tube in the sequence that the starting gapwill be ionized to prepare the nexty tube so that it will conduct whenthe next input impulse is received.

The stepping of the conducting condition oi the tubes of the ring orchain -is obtained by varying the anode potentials supplied to the twogroups of tubes between a high potential which will support conductionand a `low potential which will not be capable o f supportingconduction, the relation between the potentials being such that, whenhigh potentialis supplied to one group of tubes, low potential issupplied to the other group, rwith the high and low potential conditionsbeing reversed each time it is desired to step. the ring.

In the embodiment which is being describedy to explain the invention,vthe anode potentials for the two groups of tubes are `derived from theentry device, which also serves as an anode potential control means towhich the input impulses are applied and which can be operatedalternately to one or the other of two stable operating conditions bythe impulses. The anode potentials are derived from the entry device-oranode potentialcontrol means in such a manner that they can vary `withthe differentoperating conditions of the means. When the control meansis in one operating condition, the anode potential which is supplied toone of said groups of tubes will be high enough to cause conductionv ina tube of that group; but, when the control means is in its otheroperating `condition, the anode potential which is supplied to this onegroup of tubes will have been reduced to a value which will not supportconduction in the tubes of the group. In a similar manner, the anodepotential which is supplied to the other group of tubes will be high orlow, depending on the operating condition of the potential controlmeans. The relation between the anode potentials which are supplied tothe two groups of tubes is such that, whenever the high anode potentialis supplied to `one group of tubes, the low potential will be suppliedtothe other group of tubes.

In the novel' circuit, thereiore, the combination of the groupingof thetubes and the variation of the anode potentials applied to the groups,together with the floating` connections which connect the tubes in achain orring, en-

ables an extremely simple circuit to be obtained and enables the tubesof the ring or chain to be operated Aone at a time in response to inputimpulses which are applied to the anode potential control means.

The novel circuit can be used to control or operate means to produce anoutput signal in each cycle of operation of the ring when a particulartubeconducts. If the novel circuit is used as one denomination of anaccumulator, then the means which produces the output signal could beeffective as atens transfer means to enter a unit in a higher order eachtime the lower order makes a cycle of operation.

If desired, controls may be provided to cause a particular tube in thering or chain to conduct to prepare the ring or chain for step-bystepoperation.

cuit.

A further object of the invention is to provide a step-by-step-operatingelectron tube counting circuit in which the sequential operation of thetubes is effected by variations in operating potential supplied to thetubes. 1

A further object of the invention is to provide astep-by-step-operatinggcold-cathode tube ring in which conduction inthemain gap of a tube causes ionization in the starter gap in the next tubein sequence in the ring and in which lthe stepping of the operation ofthe ltubes is controlled by varying the anode-cathode operatingpotentials supplied to the tubes in response to input signals.

With these and other, incidental, objects in view, the inventionincludes certain novel features of construction and combinationsofparts,

a' preferred form or embodiment of which is heref inafter described withreference to the drawings which Yaccompany and form a part of thisspecification. Y Of the drawings, Fig. lis a circuit diagram of one ofthe novel counting circuits including a counting ring with means V-topreset the ring to a predetermined condition and including means toproduce an output signal for each cycle of operation of the ring. Fig. 2is a section Vthrough one of the coldcathode tubes used in thering,showing the spacing of the electrodes. l

Fig. 3 is a perspective view of the tube of Fig. 2, showing vthe shapeand relative positioning of the electrodes. Y

v Detailed description In order that v the invention may be more clearlyexplained, it will be described as embodied in a counting ring which issuitable for use as a denominational order of a decimal accumulator. Itis to be understood that the invention is not limited to its use as acounting ring or to the use of ten tubes in the ring, because it issusceptible of use wherever sequential operation of ,tubes is desiredand with. different numbersv of tubes in the ring, theonly limitationbeing that, when connected to 'operate as av ring, an even number oftubes must be provided. It will also become obvious fromthe followingdescription that additional tubes can be included in the ring circuitwithout requiring any additional circuit elements of resistance orcapacitance.

In the following description, values of potential with reference toground and values of resistance and capacitance, -as well as tube types,will be given. It is not intended that the invention be limited to theseparticular potentials or to the values of resistance specified herein,because the potentials used are merely selected as convenient potentialsfor the disclosure, and the values of the circuit elements of resistanceand .capacitance given correspond in relative value to the potentialschosen. ,It is also obvious that other types of tubes may be used andalso that It is an object of the invention, therefore, t0, 10.

provide a simplied electron tube counting cirother potentials may beused, and, when this occurs, the values of the circuit elements can beadjusted accordingly to maintain the proper relationship between thevarious parts of the circuit.

Excellent results have been obtained from circuits constructed accordingto the invention, using values of resistance, capacitance, andpotentials to be given. These circuits also showed ,good tolerancetovariations in the positive potential supply and in the size of inputimpulses which were supplied thereto.

The circuit of Fig. 1 includes an entry device which is operated byinput impulses and which Yis made up of a pair of thyratrons 50 and 5|and l an associated resistance network from which are derived the `highand low anode potentials; a ring of digit-representing tubes which areoperable step by step in sequence; and an output signal tube 52, whichmay serve as ya tens transfer tube to send an impulse to the next higherdenomination each time the ring exceeds its capacity when the ring isused as one denomination of an accumulator.

In order to simplify the showing of the cir- Clit, (60,!) ((11)) ((21,)((7,1) ft8l) ((9)) digit-representing tubes of the ring have been shown,because the circuits and operation of the 3 to "6 digit-representingtubes are the same as those shown andwill be clear from Vthose circuitsWhich are shown.

The entry device has the vinput impulses applied thereto and operates tocontrol the stepping of the operating condition of the ring Vbycontrolling the application of high and low anode potentials to thegroups of tubes of the ring. The tubes 50 and 5I of the entry device aretetrode thyratrons, of the type sold under the designation 2050, whichtubes are connected in a trigger circuit operable alternately to eitherof two stable states.

The anode of tube 50 has potential supplied thereto over point 53,resistor 54, of 10,000 ohms. conductor 55, normally-closed contact ofreset switch 56, conductor 51, and terminal 58, to which +325 volts isapplied. The anode of tube 5I is similarly supplied with potential bybeing connected over point 59 and resistor 60, of 10,000 ohms, toconductor 55.

Points 53 and 59 in the anode circuits are coupled by a blow-outcapacitor 6I, of .05 microfarad, which transmits the negative impulse,which is created as a tube begins to conduct, to the other tube, whichis already conducting, vto extinguish the previously-conducting tube.This connection insures that only one of the trigger tubes will beconducting at a time,

'Ihe cathode of tube 50 is: connected to gro-und over point 65 andresistor 66, of 30,000y ohms. Point 55 is coupled to the center tap ofthe secondary of a filament transformer 6'! and also to ground over a.'l-microfarad capacitor. rIhe potential of point 65 will vary from alow value when tube 50 is not conducting to a high value when it isconducting.

Similarly, the cathode of tube 5l is .connected to ground over point 68and resistor 89, of 30,000 ohms, point 68 being connected to the centertap of a separate filament transformer l0 for this tube' and to groundover a .Ol-microfarad rcapacitor. The potential .of point -68 will alsovary 'between a high value and la low value, depending on the conducting status of tube 52.

The shield grid and the control grid of tube '50 are connected together,and a normal negative blocking bias' is applied over point 1|, resistor12, of 250,000 ohms, point 13, resistor 14, of 250,000 ohms, andterminal 15, which is supplied with a potential of 16.5 volts.

Terminal also supplies blocking potential to the shield grid and thecontrol grid of tube 5l, Wihichare tied together and are connected tothe terminal over point 16 and resistor 11, of 470,000 ohms.

'Input impulses from an input source vshown generally at 18, which mightbe a source of digitrepresenting impulses, as disclosed in the MummaUnited States Patent No. 2,404,739, or any `source of positive impulses,are applied over coupling capacitors 19 and 80, each of 50micromicrofarads, to points 1l and 16 and will cause tubes 50 and 5l toconduct alternately. This `operation of the tubes will cause one of thepoints 65 or 68 to have a highpotential and the other a .low potential,which potentials will be reversed when a further impulse reverses theoperation of the trigger pair, The potentials of the points 65 and 68are applied as the anode potentials of ,thel two groups ofdigit-representing tubes making up the ring of cold-cathode tubes, whichare operable step by step as counting progresses.

.- It is. to be understood that the entry device which is shown in Fig.l for causing the stepping of the operating conditiono-f the ring ismerely illustrative of one form of device for supplying anode potentialsand varying these potentials to cause the stepping of the ring.

Other forms of trigger pairs and other potential- Varying means arewithin the purview of the invention solong as they can supply highenoughistics lwere not available, a suitable tube was developed. Fig. 3 is anenlarged perspective View of the tube, while Fig. 2 is a side elevationwhich shows the side-spacing of the electrodes.

The tube is provided with a plurality of electrodes, including, inorder, a cathode, K; two igniters, I1 and I2; two further electrodes,one of which may be considered as a probe, P, and the other may beconsidered as an auxiliary anode, Ax and an anode, A. Y

The cathode K, which is a substantially round flat disc about .75 of aninch in diameter, is made of a sheet 85 of magnesium and a sheet 86 ofnickel, which are mounted on a support with the magnesium sheet facingthe anode'. The two sheets are fastened together vat .the support butare merely clipped together by a clip y61 at a point remote from thesupport to allow relative movement and prevent buckling due to thediiferent coeiiicients of expansion of the two metals.

Adjacent the cathode are .the two igniter electrodes, which are made of.02 of an inch nickel wire.

cathode parallel thereto and is spaced about .032y

Igniter I1, which extends across the of an inch therefrom, canycooperate with the cathode to form a starting gap. Igniter I2 alsoextends across the cathode, parallel thereto, but runs approximately atright angles to igniter I1 and is spaced about .075 of an inch from thecathode. The igniter I2 can be used with either the cathode or the'igniter I1 to form a starting gal)- f .l flat annular member made and itis mounted parallel to the cathode about .16 of an inch therefrom. Thisprobe lies adjacent the anode-'cathode discharge path and can beinfluenced greatly by a discharge in the tube.

The auxiliary anode Ax also is made ofy .02 kof an inch nickel wire, iscurved to generally follo-w the shape of the probe P, lies between theprobe and theanode A, and also can be influenced Aby discharge inthe'tube.r v VThe anode `A is a disc of nickel about .25 of an inch indiameter. It is mounted on a rsuitable support parallel to the p-robeand about .16 of an inch therefrom:

The supports for the various electrodes are insulated and extend througha press 88. at the bottom of the tube.

This tube was activated bypulse bombardment of the cathode and the probeand is lled with argon gas at a pressure of l2 millimeters of mercury. v

This tube-has excellent operating characteristics and is very flexiblein its use, since the several electrodes intermediate the anodeand thecathode can be used in a variety of ways as igniters, as auxiliarycathodes, or as probes, as required in the circuit inwhich the tube isto be used.

A tube constructed as above, will have a striking potential from igniterI1 to cathode K of about 90 volts; from igniter I2 to cathode K of about11i() volts; from probe P` t0 cathode K of about 180 volts and fromanode A to cathode K of about 300 volts. With the tube conducting andpassing 5 milliamperes, it has a'drop of about 67 volts from the cathodeto either igniter I1 or I2 and a drop of about 75 volts from the cathodeK to the anode A, and the 'probe P will be about 60 volts more positivethan the cathode.

As` shown in Fig. l, the even numbered` digitrepresenting tubes havetheir anodes connected together and over conductor 89 Ato point 65 inthe `cathode circuit of tube 50, from which point they will be suppliedwith a potential which is high enoughto cause conduction in any tube ofthe group When the tube conducts, but which will be low enough so as notto support conduction in any tube of the group when tube 50 is non-conyducting. Similarly, the anodes of the odd numbered tubes are connectedtogether and over conductor to point 68 in the cathode circuit of tubeA5I, from which point they will besupplied withy a high potential whentube 5I conducts and o a low potential when tube 5I is non-conducting.Since only one of the tubes 50 and 5| is conducting lat a time, :onlyone group of tubes will have high potential applied thereto, and, whenone of vthe groups has high operating vpotential applied thereto, theother group willvhave low potential supplied thereto.

It is to be noted that, if it is-desired to obtain greater potentialvariations for.v the anodes of the .groups of, tubes than are possiblefrom the variations in the cathode potentials of the trigger pair, eachgroup of tubes can be coupled to the trigger pair over a high-vacuum,phase-reversing amplifying tube. The anodes of the group of tubes areconnected to the anode of the amplifying tube, which has high enoughpotential supplied to its anode over an impedance to provide the.desiredrange I,of potential Variatiomhas its icathode connected toground; and has its control electrode coupled to the point, as 65 or 68,in the .cathode circuit of the trigger pair. Variations in the point inthe cathode circuit of the trigger pair will control conduction in theamplifying tube vto produce the required potential variations at theanodes of the tubes of the group.

The cathodes of the even numbered digitrepresenting tubes (Fig. 1) areconnected together and to ground over a common resistor` v19|, of 22,000ohms, and the cathodes of the "odd numbered tubes are connected togetherand to ground over resistor 92, of 22,000 ohms.

Since the anodes of the even Ydigit'repre- `senting tubes are connectedtogether and to the same potential-supplying point and the cathodes ofthese tubes are connected ,together and to ground over a commonresistor, it is seen that a comm-on operating potential supply isprovided for the group of tubes. Similarly, there is a common operatingpotential supply for the odd digit-representing tubes.

The chain connections between the tubes eX- tend from the probe of onetube to the igniter I1 of the next tube in the series; for example, fromthe probe of the tube to the igniter I1 of the l tube; from the probe ofthe 1 tube to the igniter I1 of the 2 tube, etc. These connections,which are shown at 93, are direct wire connections which contain noimpedance elements and are floating, .since they have no ldirectconnection with any potential source.

When the digit-representing tubes are connected to form a ring, as shownin Fig. 1, the probe of the 9 tube is connected over a conductor 94 tothe igniterV I1 of the "0 tube. If the ring is to control some othermeans to `generate a signal each time the ring passes from arepresentation of 9 to a representation of 0 and the connection betweenthe "9 tube and the 0 tube is used in the control of this means, then .a

rectifier 95, such as half a 6I-I6 type tube, can be included in theconnection to enable the proper control to be -dbtained, as will beexplained-more Y full-y hereinafter.

The grouping of the tubes with a separate operating potential supply foreach group, and the floating chain connections between the tubes in thegroups, enable the stepping of the conducting tube in the ring to beobtained by controlling the potential supplied to the groups.

The ring operates in the following manner. If the ring is operating torepresent a digit, as 1, then the l digit-representing tube will beconducting. A-t this time, the odd Vgroup of tubes will have high anodepotential applied thereto, due to conduction in tube l, andthe evengroup will have low anode potential applied thereto, due tonon-conduction in tube 50.

The probe of the l digit-representing tube is in the ionized medium ofthe conducting tube, and, due to conduction in the tube, will becomeeffective to cause the starter gap of the 2" tube, between the igniterI1 to which it is connected and the cathode, to become ionized andpasssumcient starter gap current to cause main gap 'breakdown of the 2tube. The ionization in the starter gap of the 2 tube cannot spread tothe main gap, and the 2 tube cannot become .conducting at this time,because the low anode potential which is being supplied to thieanodes ofthe `even group of tubes will not support conduction in .any of them.

.It is to be noted that, while the yother tubes .of the odd .group .arebeing supplied with high ano de'potential at this time, none will -berendered conducting, because the anode 'potential'which is applied isnot high enough to cause a breakdown in the main gap directly betweenthe anode and the cathode of any of them unless there has been aprevious breakdown `at the starter gap. There Awill be no breakdown ofthe starter gap in these tubes, because the igniter I1 in each of thesetubes is connected to a probe in a non-conducting even tube, and thecathodes of these tubes, which are connected to the cathode of theconducting l tube, will be more positive, dueto conduction in that tube.This will cause insuffi- -cient voltage across the starter gaps tobringabout ionization therein.

There will be no breakdown of the starter vgaps in the tubes of the evengroup other than the 2 tube, because theigniter vI1 in each of thesetubes is connected to a probe in a non-conducting odd tube, and thepotential across the gap will be insuiiicient to cause its breakdown.

Wi-th the ring in the l digit-representing condition, in which the ltube is conducting and the starter gap vof the 2 tube is ionized, thenext input impulses will be effective in the 'following manner to 4causethe 2 tube to conduct and the 1 tube to cease conducting. lThe positiveinput impulse from the source 18 will be impressed `on the ventry deviceand will cause tube 5,0 to be fired and rendered conducting. -As tube 50res, it will cause the potential of point 55 and the anodes of :the eventubes to become high and con-duction to occur in the main gap of the Y2tube, in which the starter gap had been ionized. Also, as the tube 50res, it will send a negative impulse over the blow-out capacitor 6|V tothe tube 5I to extinguish this tube, which causes the anode potential ofthe odd tubes to drop to a value which will not support conduction, andthe l digit-representing tube will cease conducting. The starter gap ofthe l tube also will not be ionized at this time, because the probe ofthe 0' tube, to which igniter I1 of the 1' tube is connected, is nolonger in the ionized medium of a conducting tube, since the 0 tube isnot conducting.

Conduction in the 2 digit-representing ,tube will cause i-ts probe to beeiective to cause the starter gap of the 3 digit-representing tube tobecome ionized.

In a similar manner, the next input impulse will lire tube :51, whichwill apply high lanode potential to the odd tubes to cause conduction inthe main gap of Athe 3 tube. The ring of tube 5| will extinguish tube50, which in turn lowers the anode potential of the even tubes andextinguishes the con-ducting "2 tube.

Subsequent impulses will cause further stepby-step operation of thedigit-representing tubes, the probe-to-igniter connections selecting theY tubes which are to be operated .in the sequence.

VIn the form shown in Fig. 1, the 9 digit-representing tube primes vtheroutput signal tube 52,

' vso that the youtput signaltube will be operated my' thep'same inputimpulse which causes the 0 tube to operate following an operation of the9 tube.

The output signal tube 52 is a ieirode tinyraimii` of the 2050 type andis connected in a vself-extinguishing circuit. The tube is provided withan anode potential of about +250 volts, derived from a tap 96 of apotentiometer 91, of 40,000 ohms, which is connected between terminal 58and ground, the connection extending from the tap 96 over resistor 98,of 250,000 ohms, point` 99, and resistor |00, of 1,000 ohms, to theanode, with point 99 connected to ground over a .005- microfaradcapacitor. Y Y

The cathode of tube 52 is connected to ground over point |05, resistor|00, of 250,000 ohms-,point |01, and resistor |08, of 250,000 ohms, withpoint |05 coupled to ground over a .005-microfarad capacitor and with anoutput signal conductor V|09 connected to point lill to receive apositive output impulse each time the tube conducts. The circuitconstants in the anode and cathode circuits are such that the tube willbe extinguished automatically shortly after it is red.

The shield grid and the control grid of tube 52 are connected togetherand over point IIU and resistor Hl, of 1 megohm, to terminal H2, whichhas -39 volts applied thereto. The grids are also connected to groundover a 50G-micromicrofarad capacitor and are connected over a resistorH3, of 1 megohm, and a tap H4 to a resistance network which includes aresistor H5, of 2.2 megohms, a resistor H6, of 1 megohm, and a resistorIIT, of 2.2 megohms connected in series between the probe of the 9 tubeand ground, the tap H4 cooperating with resistor H6 to control theeffect of the potential variations of the probe of the 9 tube on thegrids of the output signal tube 52.

The grids of the output signal tube are also coupled from point H0 overa capacitor IIB, of 50 micro-microfarads, and conductor H9 to the sourceof impulses 18, so that each of the input impulses will be impressed onthe grids. The normal bias which is supplied to the grids will normallyprevent the input impulses from ring tube 52, but this bias is reducedand the tube is primed to respond to the input impulses when the 9 tubeconducts. rIhe probe of the 9 tube will become positive when the 9 tubeconducts and will impress a positive potential on one end of theresistance network containing re sisters H5, H5, and lil. The tap H4 isadjusted on the resistor IIB to enable the positive potential on theprobe to be reflected on the grids in such a manner that the tube 52will be primed and can respond to input impulses only when the 9 tubeconducts.

The rectifier 95 prevents the potential rise of the igniter I1 of the 0tube, when that tube is conducting, from priming the output signal tube.

will be primed when the 9 tube'conducts and will be red by the sameinput impulse which causes the 0 tube to conduct and the 9 tube to beextinguished, thereby to produce an output signal for each cycle ofoperation of the ring.

lf the countingring forms one `denomina-tional order of an accumulator,the output signal can be used to control a tens transfer means of thedelayed-action type or can be impressed on the entry device of the nexthigher order if no delay in the tens transfer entry is desired.

It is to be understood that the output signal means and the controlstherefor shown in Fig. 1

With these controls, the output signal tube 52 are merely illustrativeand are not the only formof such means or controls that may be used.An-l other control of the output signal tube 52 of Fig. 1 could bederived from the auxiliary anode Ax of the 9 digit-representing tube.Since the auxiliary anode Ax will also have a positive potential whenthe 9 tube conducts, it can be used with the circuit of Fig. 1 insteadof the probe to prime the output signal tube. When this control is used,the priming is divorced lfrom the probe-to-igniter connection betweenthe 9 and 0 tubes, and the rectiiier 95 can be eliminated.

Also, if it isdesired to re the outputsignal tube directly instead ofpriming it, either. the auxiliary anodeiAX or the igniter I2 of the 0tube can be used, since each of these electrodes becomes more positivewhen the "0 tube con.- ducts, which positive potential rise can be usedto re the output signal tube directly each time the "0 tube conducts. Ifthe ring with the output control from the O tube is one order of anaccumulator, then the entry device of the next higher order can beoperated directly from the auxiliary anode AX of the "0 tube, ifdesired, to effect vtens transfer entries therein.

While the ring of Fig. l is arranged to cause a single output signal tobegenerated for each cycle of operation, the novel circuit is notlimited to thisY use, since any desired one or more of the tubes of. thering can cause an output signal to be generated.

TheV electrodes which become more positive when conduction takes placein a tube, such as the auxiliary anode AX or the igniter I2, which arev.not used in .the ring connections, can be sensed tocontrol a means toindicate which tube is conducting, if desired.

Means have been provided to preset the circuit to zero condition. Theanode potential supply for the trigger pair, and therefrom the tubes of.the ring, extends over a normally-closed contact of the reset switch56, which is operated momentarily'in a resetting operation. The switch56 also includes a normally open contact, the relation of the contactsbeing such that, in the operation of the switch, the normally-opencontact will be closed before the normally-closed contact opens, and, inthe return to normal condition, the normally-closed contact will reclosebefore the normally-open contacts open. The normally-open contact isconnected to con- .ductor 420, thence over resistor |2I, of 3 megohms,to point T3 in the circuit to the grids of tube 50 and resistor |22, of680,000 ohms, to igniter Iiof the "0 tube of the ring andy when closedwill apply anodepotential to the grid and ,to the igniter.

n the resetting operation, therefore, positive potential'will be appliedto the grids of the tube 50 and to the: igniter Ii'of the f0 tube, andthen anode potentialv will be removed from all theY tubes to extinguishany lconducting tube. In the return movement of the switch, anodepotential will be reeestablishedxbefore the normally-open switch isopened, and tubes 50, and 0 Will con'- duct. When the switch hasreturned to normal position,l the `positive potential which wassupLplied to the grids oftubes 50 and to the igniter Ii ofthe 0 tube willhave been removed from these electrodesand the circuit can function inthe normal manner.

While the resetting potential is shown as being applied to vthe igniterI i of the 0 tube, it is not intended i0 limit the invention 'to thisarf Y 1l` rangement; because the potential could also be applied to ytheigniter I2 to cause the O tube to be fired in the resetting operation.

' While the form of the invention shown and described herein isadmirably adapted to fulfill the vobjects primarily stated, it is to beunderstood that it is not intended to conne the invention to the oneform or embodiment disclosed herein, for it is susceptible of embodimentin various other forms.

What is claimed is:

1. rIn a device of the class described, the combination of a rstplurality of electron discharge paths; a second plurality of electrondischarge paths; a iirst operating potential supply connected to thefirst plurality of discharge paths andforming them into a rstoperational group; a second operating potential supply connected to thesecond plurality of discharge paths and forming them into a secondoperational group; means connecting the discharge paths into anoperational series, for sequential step-by-step operation, each seriesconnection extending from a4 discharge path in one group to a dischargepath in the other group and enabling the discharge in the path in onegroup to prepare the next path in the series, which is in the othergroup, for discharge therein; control means operable alternately to oneand the other of two conditions and in one condition being effective tocontrol the first and second operating potential supplies to provide apotential to one group to cause conduction in a discharge path in thatgroup and at the same time to provide potential to theI other groupwhich will not support conduction in any discharge path in that groupand in the other condition reversingv the potentials supplied to the twogroups, each reversal of the potentials supplied to the groups causing astep of advance in the operating discharge path of the series.

2. In a device of the class described, the combination of a firstplurality of electron discharge paths.; a second plurality of electrondischarge paths; a rst operating potential supply connected to the rstplurality of discharge paths and forming them into a first operationalgroup; a second operating potential supply connected to the secondplurality of discharge paths and forming them into a second operationalgroup; means connecting the dischargepaths into an operational series,for sequential step-by-step operation, using discharge paths from thefirst and second groups alternately, each series connection betweendischarge paths extending from a. discharge path in one group to adischarge path of the other group and enabling the discharge in the pathin one group to prepare the next path in the series, to which it isconnected, forV conduction therein; control means operable alternatelyto one and the other of two conditions and in one condition beingeilective to control the first and second operating potential suppliesto provide a high operatingl potential to one group to cause conductionin a discharge path in that group and at the same time to provide lowoperating potential to the other group. to prevent conduction inanydischarge path in that group and in the other condition reversing thehigh and low operating potentials supplied to the two groups, eachYchange in the operating condition of the control means from onecondition to the other causing a step of advance in the operatingdischarge path of the series.

3. The Vdevice as claimed in claim 2 in which the first operatingpotential supply contains only asingle impedance element which is commonto the discharge paths of the group; in which the second operatingpotential supply contains only a single impedanceY element which iscommon to the discharge paths of the group; and in which the connectionsfor connecting the discharge paths for operation in step-by-stepsequence include no impedance element. v

4'. The device as claimed in claim 2 in which the control means includesa pair of tubes interconnected to operate as a trigger pair alternatelyto one and the other yof two stable states in response to input impulsesto provide the two operating conditions of the control means and tocontrol the supplying of the high and low poten# tials to the groups ofdischarge paths.

Y5.r The device as claimed in claim 2 in which anadditionalelectrode isprovided in each dischargepath, which electrode will acquire adistinctive potential when conduction occurs in the path and can besensed to determine in which path conduction is occurring,

6. Ina device of the class described, the combinationl of a firstplurality of gaseous electron discharge devices; a second plurality ofygaseous discharge devices; a first operating potential supply connectedto the first plurality of discharge devices and forming them into afirst operational group; a second operating potential supply connectedto the second plurality of discharge devices and forming them into asecond operational group; means connecting the discharge devices into anoperational series in which the conducting condition of the devices isadvanced step by step, each series connection extending from a device inone group to a device in the other group and enabling thev conduction ina device in one group to prepare a device in the other group foroperation; control means operable alternately to one and to the other oftwo conditions and inone condition being effective to control the firstand second operating potential supplies to provide a high operatingpotential for one group to cause conduction in a prepared dischargedevice in that group and at the same time to provide low operatingpotential for the other group to prevent conduction in any dischargedevice in that group and in the other condition reversing the high andlow operating potentials suppliedV to the two groups; and meansoperable, at will, to operate the control' means to reverse theoperating condition thereof, each change in the operating con- -ditionof the control means from one condition to the other causing an advancein the discharge device which is in conducting condition.

7. The device as claimed in claim 6 in which the series connectionsbetween discharge devices are simply conductors and contain no circuitimpedance elements.

- 8.A The device as claimed in claim '7 in which the operating potentialsupply for each group of devices includes a single resistor which iscommon to the devices of the group and in which the series connectionsare simply conductors and include no. circuit impedance elements.

9.'In a. device of the class described, the combination of a firstplurality of electron tubes; a second plurality of electron tubes; afirst operating potential sup-p-ly connected to the first plurality oftubesland forming them into a rst operational group; a second operatingpotential supply connected to the second plurality of tubes and formingthem into a second operational group; means connecting the tubes into anoperational series, using tubes from the first and second groupsalternately; control means operable alternately to one and the other oftwo conditions in response to input impulses and in one condition beingeffective to control the first and second operating potential suppliesto provide a high operating potential to one group' to cause conductionin a tube in that group and at the same time to provide low operatingpotential to the other group to prevent conduction in any tube in thatgroup and in the other condition reversing the high and low operatingpotentials supplied to the two groups; and means for supplying inputimpulses to the control means, each impulse reversing the operatingcondition of the control means; the supplying of operating potentials intwo groups and the varying of the operating potentials between high andlow values, together with the series connections between the tubes,causing the tubes to be operated one at a time in sequence.

vl0. In a device of the class described, the combination of a firstplurality of electron tubes; a second plurality of electron tubes; afirst operating `potential supply connected to the first plurality oftubes and forming them into a first operational group; a secondoperating potential supply connected to the second plurality of tubesand forming them, into a second operational group; means connecting thetubes into an operational series for operation one after another instep-by-step sequence, using tubes from the rst and second groupsalternately, said connections being floating connections extendingdirectly be'- tvveen tubes of ydifferent groups and enabling conductionin a tube in one group to prepare a tube in the other group foroperation; control means including a pair of tubes interconnected tooperate as a triggerpair which is operable alternately to one and theother of two conditions in response to impulses, and in one condition iseffective to control the first and second operating potential suppliesto provide a high operating potential to one group to cause conductionin a prepared tube in that group `and at the same time to provide lowoperating potential to the other group to prevent conduction in any tubein that group and in the other condition is eiective to reverse the highand lovv operating potentials supplied to the two groups; means tosupply impulses to the control means to cause the trigger pair tooperate to said one and said other conditions; the supplying ofoperating potentials to the two groups and the varying of the operatingpotentials between hlgh and low values, together with the seriesconnections between the tubes, enabling each change 1n the operatingcondition of the control means from one condition to the other to causean advance in the tube in which conduction takes place.

1l. In a device of the class described, the combination of a pluralityof gaseous electron tubes, each tube having at least an anode and acathode forming a main gap, an igniter cooperating-mth the cathode toform a starter gap, and a probe located in the ionizable medium of themain gap and capable of exerting a control when conduction occurs in themain gap; a first common anode-cathode potential supply connected tohalf the tubes and forming them into a first operational group; avsecond common anode-cathode potential supply connected to the otherhalf of the tubes and forming'them into a second operational group;means to control said first and second anode-cathode potential suppliesto provide a high anode potential to one group to cause conduction inthe main gap of a tube in that group which has its starter gap ionizedand at the same time to provide a low anode potential to the other groupto prevent conduction inany tube of that group, said control means beingoperable to reverse the high and low condition of the anode potentialsupplied to the groups; `means connecting the tubes for connection in aseries', using tubes of the first and second groups alternately, theconnection between adjacent tubes of the series extending from the probeelectrode in atube of onev group to the igniterl in thel starter gap ofthe tube of the other group, and enabling conduction in the tube inwhich the probeis located to ionize the starter gap of the next tube ofthe series; and means to operate vthe control means at Will to reversethe high and low condition of the anode potential supplied to the groupsthereby to cause a stepping of the operating con'- dition of the tubes.

l2. The device as claimed in claim 1l in which the anode-cathodepotential supply for each group of tubes contains but one circuitimpedance element, a cathode resistor, which is common to the tubes ofthe group; and in which the probe-to-igniter connections between tubesare simply conductors and contain no impedance elements whereby aminimum of impedance relements are provided in the circuits of Vthe twogroups of tubes. l

13. The device as claimed in claim ll in which the probe-to-igniterconnections are floating connections and have no connection with outsidepotential sourcesbut acquire potential-only from conduction in the tubesin which the probe and the igniter are located. l

14. The device as claimed in claim 1l in which the tubes are connectedin a closed series or'ring and which includes an output signal means,and means connecting the output signal means to a probe in one of saidtubes to be controlled thereby to generate an output signal upon eachcycle of operation of the ring.

15. In a device of the class described, the combination'of a pluralityof gaseous electron tubes,V

each tube having at least an anode anda cathode forming a main gap, anigniter cooperating with the 'cathode to form a starter gap, and a probelocated in the ionizable medium of the main gap and capable of exertinga control when conduction occurs in the Vmain gap; a rst commonanode-cathode potential supply connected to half the tubes and formingthem into a first operational group; a second common anodecathodepotential supply connected to the other half of the tubes and formingthem into a second operational group; means to control said first andsecond anode-cathode potential supplies to provide a high anodepotential to one group to cause conduction in the main gap of a tube inthat group which has its starter gap ionizedand-at the same time toprovide a low anode potential to the other group to prevent Yconductionin any tube of that group, said control means being operable to reversethe high andlowvcondition of the anode potential supplied tothe groups;means connecting the tubes for operation in a series, using tubes of theiirst and second groups alternately, the connection between adjacenttubes of the series extending from the probe electrode in a tube of onegroup to the igniter in the starter gap of the tube of the other group,and enabling conduction in the tube in which the probe is 1ocated' toionize` the starter' gap'v of the next tube ofthe series; means tooperate the control means at. will to reverse the high and low conditionof the. anode potential supplied to the groups thereby to cause astepping of the operating condition of the tubes; and a furtherelectrode in each tube in the ionizable medium thereof, which electrodewill acquire a positive potential when its tube conducts and whichelectrode can be sensed to indicate if the tube is conducting. v

16. In a device of the class described, the combination of a rstplurality of electron tubes; a second plurality of electron tubes, eachtube having at least an anode, a cathode, a probe electrode, and anigniter cooperating with the cathodeto form a starter gap; a rst commonanodecathode potential supply connected to the first plurality of tubesand forming them into a first operational group; a second commonanodecathode potential supply connected to the second plurality of tubesand forming them into a second operational group; means including a pairofelectron tubes interconnected to operate as a trigger pair toeither oftwo stable states in response' to input impulses to control said firstand second. potential supplies` to provide a high anode potential to onegroup to cause conduction in a tube-of that group which has its startergap ionized andV at the same time to provide a low anode potential tothe other group to prevent conduction in' a tube of that group, saidcontrol means when in the other of said states being operable to reversethe high and loW anode potentials supplied to the groups; meansconnecting all the tubesl intoI an operational ring, using tubes fromthefrst and second groups alternately, each connection extendingdirectly from the probe electrode of a tube in one group to the igniterof a tubeY in the other group and enabling the effect of conduction in aconducting tube on the probe thereof to ionize the starter gap of thetube in the other group to rcondition that tube for operation; and inputmeans for causing input impulses to operate the trigger pairA of thepotential supply control means to cause a reversal of the high and lowanode potentials supplied to the groups; the supplying of anode-cathodepotentials in two groups and the varying of their anode potentials inresponse to impulses, together with the serial probe-to-conductioncontrol-electrode connections between tubes, causing the tubes to beoperated one at a time in sequence.

l'l. In a device or"l the class described, the combination of a firstplurality of electron tubes; a second plurality of electron tubes, eachtube being a cold-cathode tube having at least an anode, a cathode, aprobe electrode, and an igniterl electrode cooperating with the cathodeto form a starter gap; a first common anode-cathode potential supplyconnected to the rst pluralityY of tubes and forming them into a rstoperational group; a second common anode-cathode potential supplyconnected to the second plurality of tubes and forming them into asecond operational group; means to control said rst and second potentialsupplies to provide a high anode potential toV one group to causeconduction in a tube of that group which has its starter gap ionized andat the same time 'a low anode potential to the other group to preventconduction in a tube of that group, said control means being operable toreverse the high and 10W condition of' the anode potential supplied tothe groups each time an impulse is received; means connecting all thetubes into an operationalv series,

using tubes-from-the first*V and second groups al,- ternately, eachconnection extending directly froml the probe electrode of a tubeinonegroup to the igniter electrode of a tube in the other group to enableconduction in the tube of the one group to ionize the starter gap of thetube inthe other group to condition this tube for operation; and inputmeans for causing an operation of the potenti-al supply control means toreverse the high and low conditions of the anode potential supplied tothe. groups; the supplyingV of anode-cathode potentialsv in two groupsand the' varyingv of their anode potentials in response to impulses,together Withthe serial probe-toigniter electrode connections betweentubes; causing the tubes to be operated one at-a time in sequence. i

18. In a device of thel class described, the com.- bination ofl aplurality'of gaseous electron tubes; each tube having at least an anodeand acathode forming a main gap, an igniter cooperating with the cathodeto form a starter gap, and a probe located in the main gap between theanode and the cathode and capable of exerting arlexternal control whenconduction occursI inthe main gap; a circuit connecting the cathodes ofhalf of the: tubesv together andA over acommon impedance toa cathodepotential supply to-form a first group of tubes; a circuit connectingthe cathodes of thev other half of the tubes together and over a commonimpedance to a cathode potential supply to form a secondA group oftubes; a circuit connecting the. anodes of the first group of tubestogether and to arst source of anode potential; a circuit connecting theanode-s of the second group of tubes together and to a second source ofanode potential; means to control said rst and second sources. of anodepotential to-provide a high anode potentialto one group'tocauseconduction in the main gap of a tube inthat group which has its startergap ionized and at the same time to provide a low anode potential to theother group to prevent conduction in any tube-of that group, saidcontrol means being operable* to reverse the high and low condition ofthe anode potential supplied to the groups; means connecting the tubesfor operation in a series using tubes of the iirst and second groupsalternately, the connection between adjacent tubes of the series being afloating connection extending from the probe electrode in a tube of onegroup directly to the igniter in the starter gap of the tube of theother group andl to no other' source ofpotential, and enablingconduction in the tube in which the probe is located to cause thestarter gap of the next tube of thev series to be ionized; and means tooperate the control means at will toreverse the high and. low conditionof the anode potential supplied to the groups'therebyy to cause astepping of the operating condition of the tubes.

19; In a device of the class described, the combination of a rstplurality of electron tubes; a second'plurality of electron tubes, eachtube having at least an anode, a cathode, a probel electrode which iscapable of exerting an external control when the tubeconducts, and anigniter cooperating withY the cathode to form av starter gap; a iirstcommon anode-cathode potential supply connected to the rst plurality ofVtubes and forming them intoa rst operational group; a second commonanode-cathode potential supply connected to the secondplurality ofVtubes and forming them into a'second operational group; meansconnecting: all the. tubes into an operational ring, using tubes fromthe first and second groups alternately, each connection extendingdirectly from the probe electrode of a tube in one group to the igniterof a tube in the other group and enabling the probe of a conducting tubeto exert its control and ionize the starter gap in the tube of the othergroup to condition that tube for operation; means including a pair ofelectron tubes interconnected to operate as a trigger pair to either oftwo stable states in response to input impulses and effective in one ofsaid states to control said rst and second potential supplies to providea high anode potential to one group to cause conduction in a tube ofthat group which has its starter gap ionized and at the same time a lowanode potential to the other group to prevent conduction in a tube ofthat group, said trigger pair when in the other of said states beingoperable to reverse the high and low condition of the anode potentialsupplied to the groups; input means for causing input impulses tooperate the trigger pair of the potential supply control means to causea reversal of the high and low anode potentials supplied to the groupsto cause the tubes of the ring to be operated one at a time in sequence;output sign nal means for generating an output signal for each cycle ofoperation of the ring; and means coupling a probe of a particular tubeof the ring to the signal means to enable the positive potential on theprobe as its tube conducts to control the output means to produce asignal.

20. In a device of the class described, the combination of a pluralityof digit-representing electron tubes, each tube being a cold-cathodegaseous electron discharge tube having at least an anode and cathodeforming a main gap, an igniter cooperating with the cathode to form astarter gap, and a probe located in the main gap between the anode andthe cathode and capable of exerting an external control when conductionoccurs in the main gap; a circuit connecting the cathodes of the evendigit-representing tubes together and over a common resistor to groundto form a iirst group of tubes; a circuit connecting the cathodes of theodd digit-representing tubes together and over a common resistor toground to form a second group of tubes; a circuit connecting the anodesof the rst group of tubes together and to a first source of anodepotential; a circuit connecting the anodes of the second group of tubestogether and to a second source of anode potential; means connecting thetubes for step-by-step operation in a ring in a digital series, usingtubes of the first and second groups alternately, the connection betweenadjacent tubes of the ring extending directly from the probe electrodein a tube of one group to the igniter in the starter gap of the tube ofthe other group, and enabling the probe, due to conduction in the tubein which the probe is located, to cause the ionization of the startergap of the next tube of the ring; means to control said rst and secondanode potential supplies to provide a high anode potential to one groupto cause conduction in the main gap of a tubev in that group which hasits starter gap ionized and at the same time to provide a low anodepotential to the other group to prevent conduction in any tube of thatgroup, said control means being operable to reverse the high and lowcondition of the anode potential supplied to the groups, each reversalenabling conduction to occur in the main gap in the tube having itsstarter gap ionized and causing cond-uction to cease in the tube whichwas previously conducting whereby to cause the stepping of the operatingcondition of the tubes; and means to operate the control means at willto reverse the high and low condition of the anode potential supplied tothe groups.

2l. In a device of the class described, the combination of a pluralityof digit-representing electron tubes, each tube being a cold-cathodegaseous electron discharge tube having at least an anode and a cathodeforming a main gap, an igniter cooperating with the cathode to form astarter gap, and a probe located in the main gap between the anode andthe cathode and capable of exerting an external control when conductionoccurs in the main gap; a circuit connecting the cathodes of the 2evendigit-representing tubes together and over a common resistor to groundto form a rst group of tubes; a circuit connecting the cathodes of theodd digit-representing tubes together and over a common resistor toground to form a-second group of tubes; a circuit connecting the anodesof the first group of tubes together and to a'iirst source of anodepotential; a circuit connecting the anodes of the second group of tubestogether and to a second source of anode potential; means connecting thetubes for step-by-step operation in a ring in a digital series, usingtubes of the rst and second groups alternately, the connection betweenadjacent tubes of the ring including no impedance elements and extendingdirectly from the probe electrode in a tube of one group to the igniterin the starter gap of the tube of the other group, and enabling thecontrol exerted by a probe, due to conduction in the tube in which theprobe is located, to cause ionization of the starter gap of the nexttube of the ring; means to control said rst and second anode potentialsupplies, said means including a pair of tubes connected to operate as atrigger pair` alternately to one and the other of two stable states inresponse to positive potential impulses, and in one of said statesproviding a high anode potential to one group to cause conduction in themain gap of a tube in that group which has its starter gap ionized andat the same time to provide a low anode potential to the other group toprevent conduction in any tube of that group, said trigger pair when insaid other state being operable to reverse the high and low condition ofthe anode potential supplied to the groups, each change in operatingstate of the trigger pair enabling conduction to occur in the main gapin the tube having its starter gap ionized and causing conduction tocease in the tube which was previously conducting whereby to cause thestepping of the operating condition of the tubes; and means tosupply'positive input impulses to the trigger pair to reverse itsoperating state to operate the control means at will to reverse the highand low condition of the anode potential supplied to the groups andcause the conducting condition on the tubes to be stepped around thering.

JOSEPH R. DESCI-I.

No references cited.

